title: Specificity of mammalian spermidine synthase and spermine synthase.
abstract: 1. The specificity of rat prostatic spermidine synthase and spermine synthase with respect to the amine acceptor of the propylamine group was studied. 2. Spermidine synthase could use cadaverine (1,5-diaminopentane) instead of putrescine, but the Km for cadaverine was much greater and the rate with 1mM-cadaverine was only 10% of that with putrescine. 1,3-Diaminopropane was even less active (2% of the rate with putrescine) and no other compound tested (including longer alpha,omega-diamines, spermidine and its homologues and monoacetyl derivatives) was active. 3. Spermine synthase was equally specific. The only compounds tested that showed any activity were 1,8-diamino-octane, sym-homospermidine, sym-norspermidine and N-(3-aminopropyl)-cadaverine, which at 1mM gave rates 2, 17, 3 and 4% of the rate with spermidine respectively. 4. The formation of polyamine derivatives of cadaverine and to a very small extent of 1,3-diaminopropane was confirmed by exposing transformed mouse fibroblasts to these diamines when synthesis of putrescine was prevented by alpha-difluoromethylornithine. Under these conditions the cells accumulated significant amounts of N-(3-aminopropyl)cadaverine and NN'-bis(3-aminopropyl)cadaverine when exposed to cadaverine and small amounts of sym-norspermidine and sym-norspermine when exposed to 1,3-diaminopropane.
mesh_terms: D000818:Animals; D002460:Cell Line; D003959:Diamines / Q000494:pharmacology; D000518:Eflornithine; D005347:Fibroblasts / Q000201:enzymology; D007700:Kinetics; D051379:Mice; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D011073:Polyamines / Q000378:metabolism; D051381:Rats; D011436:Spermidine Synthase / Q000378:metabolism*; D013097:Spermine Synthase / Q000378:metabolism*; D013379:Substrate Specificity; D014166:Transferases / Q000378:metabolism*
chemical_list: D003959:Diamines; D011073:Polyamines; D009952:Ornithine; D014166:Transferases; D011436:Spermidine Synthase; D013097:Spermine Synthase; D000518:Eflornithine